摘要
深部岩石工程安全高效开发的前提是精确获取深部的岩石力学参数。针对钻井取芯困难、成本高,室内力学试验数据少,离散性大的问题,提出了一种基于毫米压痕测试精确获取致密砂岩弹性模量的方法。采用5种常用的硬度计压头,控制最大载荷和加/卸载速率作为试验变量,对塔里木油田致密砂岩进行了大量毫米压痕测试。结果表明,采用布氏球形压头,基于Oliver-Pharr理论可以精确获取致密砂岩的弹性模量。进而,分析了布氏球形压头直径、加/卸载速率和最大载荷等试验条件对测试结果的影响规律,明确了最优试验条件;并通过有限元计算分析了受力区域应力分布规律,讨论了不同试验条件下代表性体积单元与Oliver-Pharr理论的适用性。与传统的微/纳米压痕测试相比,该方法具有测试速度快、制样方便和成本低等优点,可应用于钻井现场返排的岩屑以及难以制作标准试样的岩芯样品,为深部资源的高效开发和深部岩石工程的安全建设提供有力支撑。
The precise acquisition of deep rock mechanical parameters is required for the safe and efficient development of deep rock engineering. In response to the problems of difficult and costly coring, little data from laboratory tests and large discreteness, a method based on mm-indentation tests is developed to accurately obtain the elastic modulus of tight sandstone. In this paper, five indenters commonly used in mm-indentation test are used. A large number of mm-indentation tests on tight sandstone in the Tarim oilfield are performed by controlling the maximal load and loading/unloading rate as test variables. The results show that Brinell spherical indenters can accurately measure the elastic modulus of tight sandstone based on the Oliver-Pharr theory. In addition, the influence of test conditions such as Brinell indenter diameter, loading/unloading rate, and maximal load on test results is analyzed,and the optimal test conditions are clarified. The stress distribution in the stressed area is analyzed using FEM software, and the applicabilities of representative volume element and Oliver Pharr theory under various test conditions is discussed. Compared with the traditional micro/nanoindentation test, the proposed method has the advantages of rapid testing speed, simple sample preparation,and low cost, and it can be applied to a large number of drill cuttings returned from drilling sites as well as core samples with fracture development that are difficult to make standard samples, providing strong support for the efficient development of deep resources and the safe construction of deep rock engineering.
作者
罗宇杰
张杨
刘容妃
胡大伟
周辉
肖海斌
LUO Yu-jie;ZHANG Yang;LIU Rong-fei;HU Da-wei;ZHOU Hui;XIAO Hai-bin(State Key Laboratory of Geomechanics and Geotechnical Engineering,Institute of Rock and Soil Mechanics,Chinese Academy of Sciences,Wuhan,Hubei 430071,China;University of Chinese Academy of Sciences,Beijing 100049,China;Downhole Operation Research Department,CNPC Engineering Technology R&D Company Limited,Beijing 102206,China;Huaneng Lancang River Hydropower Inc.,Kunming,Yunnan 650000,China)
出处
《岩土力学》
EI
CAS
CSCD
北大核心
2023年第4期1089-1099,1110,共12页
Rock and Soil Mechanics
基金
国家自然科学基金(No.52179114)
中国科学院前沿科学重点研究计划(No.ZDBS-LY-DQC022)
华能集团科技项目(No.HNKJ19-H14)。
